Locking pin for digging dipper tooth



Feb. 13, 1968 Filed May 5, 1965 Q K. R. JUDKINS ETAL LOCKING PIN FOR DIGGING DIPPER TOOTH llllll if 2 Sheets-Sheet l R b BY 732 Zfi/M, 01 45 6;, ATTORNEYS Feb. 13, 1968 K. R. JUDKINS ETAL v LOCKING PIN FOR DIGGING DIPPER TOOTH 2 Sheets-Sheet 2 Filed May 5, 1965 United States Patent 3,368,293 LOiIKING PIN FOR DIGGING DIPPER TOOTH Kenneth R. Judkins and Boyd W. Irvine, .Ir., Silver Bay, Minn, assignors to Reserve Mining Company, Silver Bay, Minn., a corporation of Minnesota Filed May 5, 1965, Ser. No. 453,262 7 Ciaims. (Cl. 37-142) ABSTRACT OF THE DISCLOSURE A dipper tooth structure including a cap tooth with a blade-like digging portion and a rearwardly opening socket adapted to encase a lug forwardly projecting from the dipper. The tooth and lug have aligned openings into which a wedge-shaped locking pin is inserted to hold the tooth on the lug. The forward wall of the lug opening has an upper portion that is downwardly convergently tapered to complement the wedge-shaped pin, and a lower portion that is oppositely tapered. A flat spring is carried by a pin and projects outwardly from the pin against the lower oppositely tapered portion of the forward wall of the lug opening to hold the pin in place.

This invention relates to earth moving equipment and particularly to a tooth attaching structure for attaching teeth to the lip of an excavating dipper or bucket such as is used, for example, in open pit mining.

It has long been recognized that the penetration of a dipper or bucket into soil, ore, or other material is greatly facilitated by the provision of a plurality of protruding teeth at the leading edge or lip of the excavating device. The teeth penetrate the earth first, initially breaking the surface of the soil or ore bed whereby the lip of the digger or 'bucket can more easily enter and scoop out the material. The result is that a dipper or bucket provided with teeth will penetrate more deeply and effect a greater fill at the expenditure of less power than if the dipper or bucket were not so equipped. This factor has a direct bearing upon the amount of horsepower needed to operate a given digging apparatus, the speed with which a given amount of material can be excavated, and, ultimately, the cost of the digging operation itself.

Quite obviously, a dipper tooth is subjected to enormous stresses and considerable wear in use, and for this reason it is common practice to detachably mount the tooth in order to facilitate its easy removal and replacement. Detachable mounting of the tooth also provides the advantage that the tooth itself can be made of a more suitable grade of steel for combined mechanical and wear property requirements than would be economically or structurally practical to provide in the entire dipper or bucket.

The type of dipper tooth to which the present invention pertains is generally referred to as the cap type and comprises a tooth having a rearwardly opening socket for receiving a forwardly projecting lug carried by the dipper. In the present invention, the lug is carried by a tooth base which said base is secured to the lip of the dipper, but it will be readily appreciated that the lug may be integral with the dipper lip.

Generally, the object of this invention is to provide improved means for attaching a cap type tooth to the lip of an excavating dipper.

More specifically, it is an object of this invention to provide a detachable, cap type dipper tooth structure wherein there is provided a locking pin for locking the tooth to the tooth base, said locking pin carrying resilient, snap retention means for releasably retaining it in place, said locking pin system so designed as to provide suitable locking properties at the lower area of the tooth 3,368,293 Patented Feb. 13, 1968 base projection, thus eliminating complicated coring within the central area of said base projection. A stronger and more easily cast adapted nose section results.

Other objects of this invention and a number of its advantages will be evident from the following description of the inventon as illustrated in the accompanying drawings in which:

FIG. 1 is a top plan view of the dipper tooth of this invention attached to a dipper tooth base,

FIG. 2 is a side plan view of the dipper tooth and base of FIG. 1.

FIG. 3 is a section taken along the line 3-3 of FIG. 1.

FIG. 4 is a section taken along the line 44 of FIG. 3,

FIG. 5 is a section taken along the line 55 of FIG. 3, and

FIG. 6 is a section taken along the line 66 of FIG. 3.

Referring now to the drawings, and particularly to FIGS. 1 and 2, the embodiment of the dipper tooth structure of this invention as herein illustrated comprises a tooth base 10 and a detachable cap tooth I I. The tooth base 10 may take any suitable form and is herein illustrated, by way of example, as having a U-shaped body 12 defining a horizontal slot for receiving the leading edge or lip of a bottom wall 13 of an excavating dipper or bucket. The tooth base 10 is typically provided with reinforcing wear ribs 14 on its upper surface and laterally projecting, U-shaped ribs 15 at the sides thereof which increase the bearing surface of the tooth base against the lip of the bottom wall 13. Said tooth base may be welded to the bottom wall 13 or may be locked thereto by suitable pin means projecting through aligned openings 16 disposed in the legs of the U-shaped base adjacent to its rearwardly directed end.

The cap tooth 11 may likewise take any suitable shape adapting it for digging purposes and is herein illustrated as having a heavy, fiat, spadelike forward end portion 13 integral with a rearwardly upwardly and downwardly diverging socket portion 19. Said socket portion comprises symmetrical diverging, fiat upper and lower walis 20 and 21, respectively, closed at the sides by integral side walls 22 and 23. The walls 20 to 23 provide a rearwardly open socket 24 which is adapted to receive a forwardly projecting, substantially complementary, wedge shaped lug 25 of the tooth base 10.

Referring now to FIGS. 3-6, the upper and lower walls 20 and 21 of the cap tooth 11 are provided with vertically aligned, generally rectangular apertures 28 and 29, respectively. The apertures 28 and 29 are identical whereby the tooth 11 may be attached to the tooth base 10 with either the Wall 20 or 21 disposed upwardly. The apertures 28 and 29 are provided with like, semicircular notches 30 and 31, respectively, centrally of their forward edges, the notch 30 being clearly shown in FIG. 1. Rearwardly of the apertures 28 and 29, the walls 20 and 21 are provided with inwardly projecting bosses 32 and 33, respectively, which project inwardly of the socket 24.

The tapered, upper and lower surfaces of the lug 25 of the tooth base 10 are provided with horizontal grooves 36 and 37, respectively, which intersect said upper and lower surfaces and which extend rearwardly to the root of the lug. When the tooth 11 is attached to the tooth base 10, the lug 25 enters the socket 24 with the bosses 32 and 33 entering the horizontal grooves 36 and 37 whereby said tooth is centered relative to said tooth base.

The forwardly disposed edges of the apertures 28 and 29 slant inwardly and rearwardly, and the lug 25 is provided with a generally rectangular, vertical aperture therethrough as indicated at 38 having a forwardly disposed, slanted front wall surface portion 39 which extends downwardly past the horizontal center line of the lug 25. Below the slanted front wall surface 39 is a small, oppositely angled front wall surface portion as indicated at 40. The aperture 38 through the lug 25 is vertically aligned with the apertures 28 and 29 of the walls and 21 of the cap tooth. The front edge of the aperture 28, the notch 30, and the surface portion 39 all slant reanwardly and downwardly at the same angle.

A locking pin 45 projects downwardly through the apertures 28 and 38 and into the aperture 29. Said locking pin is generally rectangular in horizontal section to conform to the shape of the aforementioned apertures and has a downwardly and rearwardly tapering front wall surface 45 adapted to engage the front wall surface 39 of the lug when said pin is fully inserted with its upper end disposed substantially coplanar with the upper surface of the upper wall 20. Adjacent to its upper end, the locking pin 45 has a semicircular boss 47 which in terfits the semicircular notch at the forward edge of the aperture 28. It will be readily seen that the locking pin 45 is wedgingly engaged within the apertures of the lug 25 and the tooth 11 whereby said tooth is cammed rearwardly firmly against a forward face 48 of the tooth base.

The locking pin 45 is releasably retained in position by a spring 50. Said locking pin has a slot 51 in its forward face in the area where the surfaces 39 and of the aperture 38 converge. A transverse drilled hole 52 through both side walls of the slot 51 holds a pin 53. The spring 50 is made of flat spring steel material having a partial uniform bend 54 across its upper edge. The spring 50 is adapted to be inserted forwardly beneath pin 53 by rotating the uniform bend 54 beneath the pin, said installation preventing the spring 50 from dropping downwardly out of slot 51. As well shown in FIG- URE 5, the spring 50 is rectangular in form, having a centrally disposed, depending blade portion 55 which projects downwardly below the pin 53 and is adapted to engage the wall surface portion 40 of the aperture 38. The depending blade portion 55 is disposed at the same angle as the surface portion 40 whereby the spring 50 is normally disposed at the same angle. The lower end portion of the blade portion 55 is angled rearwardly as shown at 56 and projects a short distance into the aperture 29. Again referring to FIGURE 5, it will be noted that the surface portion 49 is only slightly wider than the rectangular blade portion 55 and actually comprises the bottom of an angled recess in the front wall surface 39 into which said blade portion 55 is inserted.

From the foregoing, it will be readily understood that the locking pin locks the tooth 11 to the tooth base ltl by being pressed or driven downwardly into the tapering apertures 28 and 38. The slot 51 atfords sufiicient clearance rearwardly of the spring 59, and said spring has suflicient inherent resilience, so that it can pass downwardly and move rearwardly beyond the point of convergence of the surface portions 39 and 40, after which it snaps outwardly and forwardly against the recessed surface portion 40. The angled portion 56 of the spring aids in camrning the spring toward the locking pin 45 as it passes downwardly along the surface 39 and prevents said spring from digging into said surface 39. The spring 50 prevents accidental removal of the locking pin 45 in use of the digging apparatus but allows quick and easy removal of a worn or broken tooth since it is only necessary to drive said locking pin upwardly to release the tooth 11 from the tooth base 10.

It will be understood that many changes in the details of the invention as herein described and illustrated may be made without, however, departing from the spirit thereof or the scope of the appended claims.

The advantages of the present structure will be apparent to those skilled in the art. In somewhat similar prior structures the spring locking means had its retaining engagement at the center area of the vertical section through the nose portion of the adapter, and differences between various types resided in the width,

height or number of protrusions on a conventional rubber keeper for locking purposes. In some prior art designs a steel spring, rather than a rubber-steel combination has been used to look a retaining pin in position.

The presently claimed structure affords a distinct change in several significant respects. In the first place the locking area for the present spring is at the base of the nose section of the intermediate adapter rather than at a higher position in the center of the pin-receiving aperture. In the second place the reversed tapers of the nose section of the adapter and the cap permit the spring to unload with the pin in locked position. In the third place the present design, involving the specific shapes and oriented cooperating surfaces of the tooth, key, spring, and nose piece nevertheless are derived from simple manufactured parts which can be readily assembled and disassembled. Fourthly, the spring can be manufactured at low cost and is expendable, and the assembly will function properly at all weather conditions, an important factor when work is being carried on in surface mining or grading under extremes of temperature.

What is claimed is:

1. A dipper tooth structure for mounting on the forward, digging edge of an excavating dipper, said structure comprising a lug secured to the digging edge in use and projecting forwardly therefrom; a cap tooth having a rearwardly open socket portion disposed over said lug; means defining aligned openings through said tooth and said lug; a longitudinally tapered pin disposed in said openings and locking said tooth to said lug; said aligned openings each having first tapered wall surface portions complementary to said tapered pin whereby said pin wedgingly engages in said openings; at least one of said openings having a second wall surface portion tapered in the opposite direction to said associated first wall surface portion; said pin carrying resilient means projecting laterally from said pin and bearing against said second wall surface portion to releasably retain said pin within said openings; said resilient means comprising a flat spring carried by said pin at substantially the same angle as said second wall surface portion and bearing generally fiatwise against said second wall surface portion.

2. A dipper tooth structure as set forth in claim 1; means defining a slot in the forward face of said pin, means defining a transverse hole through side walls of said slot, said hole containing a pin extending transversely across said first named pin; said spring having a partial uniform bend at its upper edge portion, said upper edge portion being disposed underneath said pin and extending partially over top of said pin, whereby said upper edge portion retains and spring in said slot.

3. A dipper tooth structure for mounting on the digging edge of an excavating dipper, said structure comprising a tooth base secured to said digging edge; said base having a forwardly tapering lug projecting forwardly from said digging edge in the direction of penetration of said digging edge; said lug being wedge shaped in vertical section; a cap tooth having a bladelike digging portion at its forward end and a rearwardly open socket at its rearward end; said tooth having rearwardly extending upwardly and downwardly divergent walls defining said socket and adapted to fit over said tapering lug and encase said lug; means defining aligned openings in said divergent walls and said lug; at least the opening in the upper of said divergent walls and the opening in said lug being downwardly convergently tapered; a locking pin disposed in said aligned openings and locking said tooth to said lug; said pin being wedge-shaped and complementarily interfitting said opening in said upper divergent wall and said opening in said lug; means defining an oppositely tapered surface portion adjacent to the lower end of said opening in said lug; said pin carrying resilient means projecting laterally from said pin; said resilient means comprising a flat spring; said fiat spring projecting downwardly at a like angle with the angle of said oppositely tapered surface portion and bearing flatwise against said oppositely tapered surface portion to hold said pin in place.

4. A dipper tooth structure as set forth in claim 3; said opening in the upper of said divergent Walls having means defining a vertical notch therein extending through the thickness of said wall; the upper end portion of said pin having a protuberance slidably, complementarily interfitting said notch.

5. A dipper tooth structure as set forth in claim 4; said opening in the lower of said divergent walls being formed in like manner as said opening in the upper of said divergent walls whereby said tooth is reversible, top for bottom.

6. A dipper tooth structure as set forth in claim 3; means defining a slot in the forward face of said pin, means defining a transverse hole through side walls of said slot, said hole containing a pin extending transversely across said first named pin; said spring having a partial uniform bend at its upper edge portion; said upper edge portion being disposed underneath said pin and extending partially over top of said pin, whereby said upper edge portion retains said spring in said slot; said spring having a centrally disposed blade portion at the same angle as said oppositely tapered surface portion.

7. A dipper tooth structure as set forth in claim 6; said oppositely tapered surface portion being narrower than said pin and the maximum width of said flat spring; the portion of said flat spring which bears against said oppositely tapered surface portion being transversely regulated in dimension to fit against said oppositely tapered surface portion; and the lower end portion of said reduced portion of said spring being angled in the opposite direction from said oppositely tapered surface portion to facilitate said spring snapping over the point of convergence of the tapers in said opening in said lug when said pin is forced into locking position.

References Cited UNITED STATES PATENTS 2,927,387 3/ 1960 Drover 37142 2,982,035 5/ 1961 Stephenson 37142 2,984,028 5/1961 Renner et al 37142 ABRAHAM G. STONE, Primary Examiner.

R. CARTER, A. E. KOPECKI, Assistant Examiners. 

